How to check if a library is 32bit/64bit built on Mac OS X?

Question

I'm having some trouble in using PyQt/SIP. I guess the SIP is compiled into 64bit, but Python has some problem with finding it.

  File "qtdemo.py", line 46, in 
    import sip
ImportError: dlopen(/Library/Python/2.6/site-packages/sip.so, 2): no suitable image found.  Did find:
        /Library/Python/2.6/site-packages/sip.so: mach-o, but wrong architecture

• How do I know if a library (so/dylib) is 32bit or 64bit?
• How do I know if my Python is 32bit or 64bit?

Answer 1

The file tool can be used to identify executables.

Example:

> file /Applications/TextEdit.app/Contents/MacOS/TextEdit 
/Applications/TextEdit.app/Contents/MacOS/TextEdit: Mach-O universal binary with 2 architectures
/Applications/TextEdit.app/Contents/MacOS/TextEdit (for architecture x86_64):   Mach-O 64-bit executable x86_64
/Applications/TextEdit.app/Contents/MacOS/TextEdit (for architecture i386): Mach-O executable i386

Answer 2

To find the available architectures in the Python instance you are using:

$ file "$( "$(which python)" -c "import sys;print(sys.executable)" )"
/usr/bin/python: Mach-O universal binary with 3 architectures
/usr/bin/python (for architecture x86_64):  Mach-O 64-bit executable x86_64
/usr/bin/python (for architecture i386):    Mach-O executable i386
/usr/bin/python (for architecture ppc7400): Mach-O executable ppc

To find whether the Python is currently running 32-bit or 64-bit (10.6 examples):

$ /usr/bin/python2.6 -c "import sys;print('%x'%sys.maxint)"
7fffffffffffffff
$ arch -x86_64 /usr/bin/python2.6 -c "import sys;print('%x'%sys.maxint)"
7fffffffffffffff
$ arch -i386 /usr/bin/python2.6 -c "import sys;print('%x'%sys.maxint)"
7fffffff
$ arch -ppc /usr/bin/python2.6 -c "import sys;print('%x'%sys.maxint)"
7fffffff

For python3, substitute sys.maxsize for sys.maxint:

$ python3 -c "import sys;print('%x'%sys.maxsize)"
7fffffff